81 lines
2.7 KiB
Java
81 lines
2.7 KiB
Java
/*
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* Copyright 2012 The Netty Project
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*
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* The Netty Project licenses this file to you under the Apache License,
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* version 2.0 (the "License"); you may not use this file except in compliance
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* with the License. You may obtain a copy of the License at:
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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* License for the specific language governing permissions and limitations
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* under the License.
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*/
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package io.netty.handler.codec.string;
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import static java.util.Objects.requireNonNull;
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import io.netty.buffer.ByteBuf;
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import io.netty.channel.ChannelHandler.Sharable;
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import io.netty.channel.ChannelHandlerContext;
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import io.netty.channel.ChannelPipeline;
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import io.netty.handler.codec.ByteToMessageDecoder;
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import io.netty.handler.codec.DelimiterBasedFrameDecoder;
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import io.netty.handler.codec.LineBasedFrameDecoder;
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import io.netty.handler.codec.MessageToMessageDecoder;
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import java.nio.charset.Charset;
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/**
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* Decodes a received {@link ByteBuf} into a {@link String}. Please
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* note that this decoder must be used with a proper {@link ByteToMessageDecoder}
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* such as {@link DelimiterBasedFrameDecoder} or {@link LineBasedFrameDecoder}
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* if you are using a stream-based transport such as TCP/IP. A typical setup for a
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* text-based line protocol in a TCP/IP socket would be:
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* <pre>
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* {@link ChannelPipeline} pipeline = ...;
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*
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* // Decoders
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* pipeline.addLast("frameDecoder", new {@link LineBasedFrameDecoder}(80));
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* pipeline.addLast("stringDecoder", new {@link StringDecoder}(CharsetUtil.UTF_8));
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*
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* // Encoder
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* pipeline.addLast("stringEncoder", new {@link StringEncoder}(CharsetUtil.UTF_8));
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* </pre>
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* and then you can use a {@link String} instead of a {@link ByteBuf}
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* as a message:
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* <pre>
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* void channelRead({@link ChannelHandlerContext} ctx, {@link String} msg) {
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* ch.write("Did you say '" + msg + "'?\n");
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* }
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* </pre>
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*/
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@Sharable
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public class StringDecoder extends MessageToMessageDecoder<ByteBuf> {
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// TODO Use CharsetDecoder instead.
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private final Charset charset;
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/**
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* Creates a new instance with the current system character set.
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*/
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public StringDecoder() {
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this(Charset.defaultCharset());
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}
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/**
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* Creates a new instance with the specified character set.
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*/
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public StringDecoder(Charset charset) {
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requireNonNull(charset, "charset");
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this.charset = charset;
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}
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@Override
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protected void decode(ChannelHandlerContext ctx, ByteBuf msg) throws Exception {
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ctx.fireChannelRead(msg.toString(charset));
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}
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}
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